Broken oil drain plug

Cheapsnake · 09-25-2014, 04:18 PM

So I.m changing oil in my 05 325i in preparation for a 4000 mile trip west tomorrow morning. Pulled the drain plug and thought it a bit strange that it didn't have a crush washer or gasket, just a taper against a not-tapered hole. Oh well, no sign of a leak so I'm good with it. Go to put the plug back in and give it a bit of extra torque, assuming this is a metal to metal seal and you can guess the rest of the story - the bolt snaps, leaving the threaded portion in the pan. Fortunately, the good engineers at BMW foresaw this and made the bolt hollow so it was an easy task to pull the threaded part out with an extractor. My bet is they purposely designed the bolt to fail before the pan threads stripped out, which would be a bigger ($) problem.

Anyway, I was fortunate to find a replacement plug at NAPA and all is well again. The oil filter came with a copper crush washer and the replacement plug came with a hard rubber washer. I didn't like the idea of no gasket at all so went with the hard rubber washer. Snugged it down and life is good again. But the question remains, should there be a gasket sealing the drain plug?

Yurick · 09-26-2014, 06:17 AM

There is typically a washer in there of sorts, whether it's copper or hard rubber as you mentioned.

Cheapsnake · 09-26-2014, 07:34 PM

Quote:

Originally Posted by Yurick

There is typically a washer in there of sorts, whether it's copper or hard rubber as you mentioned.

Exactly what I thought, but when it sealed with no washer I'm thinking BMW mustg have machined everything to be sealing surfaces. Actually, the taper lands on a hard corner of the oil pan drain hole, which likely adds to the breakage potential.